The present invention relates to an improved process for the allylation of carbon acids without the use of base. More particularly, the present invention comprises the reaction of carbon acids with allyl carbonates in the presence of palladium catalysts.
It is already known to form allylic derivatives of carbon acids by contacting the same with allylic alcohols, amines or esters in the presence of homogeneous palladium catalysts. See, K. E. Atkins, Tetrahedron Letters, 43, 3821-3824 (1970). While the process has been found suitable for strongly acid compounds such as acetylacetone it has not been found suitable for allylation of less acidic compounds such as dialkyl malonates or phenylacetonitrile. Besides resulting in no or very little conversion of the acid compounds, the reactants reduce the homogeneous catalyst resulting in a metallic precipitate.
An improved process for the allylation of carbon acids which allows for the allylation of relatively weak carbon acids is desired. Further, a process that does not detrimentally affect the catalyst system is desired.